Optical imaging lens

ABSTRACT

An optical imaging lens includes a first, a second, a third, a fourth, a fifth, a sixth, a seventh and an eighth lens elements from an object side to an image side in order along an optical axis. The first lens element and the second lens element both have positive refracting power. An optical axis region of an object-side surface of the fifth lens element is concave. A periphery region of an image-side surface of the fifth lens element, an optical axis region of an object-side surface of the sixth lens element and an optical axis region of an object-side surface of the seventh lens element are convex. Materials of the third, the fourth and the eighth lens elements are plastic. The eight lens elements are the only lens elements having refracting power in the optical imaging lens.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims thepriority benefit of a prior application Ser. No. 15/917,848, filed onMar. 12, 2018, now allowed. The prior application Ser. No. 15/917,848claims the priority benefit of China application serial no.201711482079.6, filed on Dec. 29, 2017. The entirety of each of theabove-mentioned patent applications is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to an optical imaging lens.

2. Description of Related Art

The increasing popularity of portable electronic products such as mobilephones and digital cameras in recent years lead to the prosperousdevelopment of technologies relating to image modules. An image modulemainly includes devices such as an optical imaging lens, a module holderunit, and a sensor, and the trend of pursuing light-weightiness andcompactness of mobile phones and digital cameras also facilitates thedemands for miniaturizing image modules. Due to the development of thetechnologies for charge coupled devices (CCD) and complementary metaloxide semiconductor (CMOS) devices advance and the reduction of sizesthereof, the length of the optical imaging lens mounted in the imagemodule also needs to be reduced. However, to ensure the effect andquality of photographing, the optical performance still needs to beconsidered while reducing the length of the optical imaging lens.

As portable electronic products (e.g., mobile phones, cameras, tabletcomputers, personal digital assistants, vehicle camera apparatuses,virtual reality trackers, and the like) with novel specifications emergeone after another, the development of a crucial part, i.e., the opticalimaging lens, is also diversified. The applications of the opticalimaging lens are beyond photographing and film recording but furtherinclude surveillance of surrounding as well as video recording duringdriving. Moreover, as image sensing technologies advance, the consumer'sdemands on imaging quality also become higher. Therefore, the opticalimaging lens is not only designed for a better imaging quality and asmaller lens space. Attention is also required to cope with driving orlow-brightness environments, the size of field of view and aperture, andnear infrared detection.

However, when designing an optical imaging lens, an optical lens havingboth a miniaturized size and a desirable imaging quality cannot bemanufactured by simply scaling down a lens with a desirable imagingquality. The design not only involves material properties but also needsto take practical production issues, such as manufacturing andassembling yield rates, into consideration.

Particularly, the technical level of manufacturing a miniaturized lensis higher than that of manufacturing a traditional lens. Therefore, howto manufacture an optical imaging lens meeting the needs of consumerelectronic products and facilitate the imaging quality of such opticallens has been an issue of this field.

SUMMARY OF THE INVENTION

One or some exemplary embodiments of the invention provide an opticalimaging lens capable of maintaining a preferable optical performanceunder a condition that a system length of the optical imaging lens isreduced.

An embodiment of the invention provides an optical imaging lensincluding a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element, a sixth lenselement, a seventh lens element, and an eighth lens element sequentiallyarranged along an optical axis from an object side to an image side.Each of the first to eight lens elements includes an object-side surfacefacing toward the object side and allowing imaging rays to pass throughand an image-side surface facing toward the image side and allowing theimaging rays to pass through. The first lens element has positiverefracting power. The second lens element has positive refracting power.An optical axis region of the object-side surface of the fifth lenselement is concave, and a periphery region of the image-side surface ofthe fifth lens element is convex. An optical axis region of anobject-side surface of the sixth lens element is convex. An optical axisregion of an object-side surface of the seventh lens element is convex.Materials of the third, the fourth and the eighth lens elements areplastic. The eight lens elements are the only lens elements havingrefracting power in the optical imaging lens.

An embodiment of the invention provides an optical imaging lensincluding a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element, a sixth lenselement, a seventh lens element, and an eighth lens element sequentiallyarranged along an optical axis from an object side to an image side.Each of the first to eighth lens elements has an object-side surfacefacing toward the object side and allowing imaging rays to pass throughand an image-side surface facing toward the image side and allowing theimaging rays to pass through. The second lens element has positiverefracting power. An optical axis region of the image-side surface ofthe third lens element is concave. An optical axis region of theobject-side surface of the fifth lens element is concave, and aperiphery region of the image-side surface of the fifth lens element isconvex. An optical axis region of an object-side surface of the sixthlens element is convex. An optical axis region of an object-side surfaceof the seventh lens element is convex. Materials of the first, thefourth and the eighth lens elements are plastic. The eight lens elementsare the only lens elements having refracting power in the opticalimaging lens.

Based on the above, the optical imaging lens according to theembodiments of the invention is effective in terms of the following. Bydesign and arranging the concave/convex shapes of the object-sidesurfaces or image-side surfaces of the lens elements, the opticalimaging lens is still provided with an optical performance capable ofovercoming aberrations and renders a desirable imaging quality under thecondition that the system length of the optical imaging lens is reduced.

In order to make the aforementioned and other features and advantages ofthe invention comprehensible, several exemplary embodiments accompaniedwith figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic diagram illustrating a surface shape structure ofa lens element.

FIG. 2 is a schematic diagram illustrating surface shape concave andconvex structures and a light focal point of a lens element.

FIG. 3 is a schematic diagram illustrating a surface shape structure ofa lens element according to Example 1.

FIG. 4 is a schematic diagram illustrating a surface shape structure ofa lens element according to Example 2.

FIG. 5 is a schematic diagram illustrating a surface shape structure ofa lens element according to Example 3.

FIG. 6 is a schematic diagram illustrating an optical imaging lensaccording to a first embodiment of the invention.

FIGS. 7A to 7D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the first embodiment.

FIG. 8 shows detailed optical data of the optical imaging lens accordingto the first embodiment of the invention.

FIG. 9 shows aspheric parameters pertaining to the optical imaging lensaccording to the first embodiment of the invention.

FIG. 10 is a schematic diagram illustrating an optical imaging lensaccording to a second embodiment of the invention.

FIGS. 11A to 11D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the second embodiment.

FIG. 12 shows detailed optical data of the optical imaging lensaccording to the second embodiment of the invention.

FIG. 13 shows aspheric parameters pertaining to the optical imaging lensaccording to the second embodiment of the invention.

FIG. 14 is a schematic diagram illustrating an optical imaging lensaccording to a third embodiment of the invention.

FIGS. 15A to 15D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the third embodiment.

FIG. 16 shows detailed optical data of the optical imaging lensaccording to the third embodiment of the invention.

FIG. 17 shows aspheric parameters pertaining to the optical imaging lensaccording to the third embodiment of the invention.

FIG. 18 is a schematic diagram illustrating an optical imaging lensaccording to a fourth embodiment of the invention.

FIGS. 19A to 19D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the fourth embodiment.

FIG. 20 shows detailed optical data of the optical imaging lensaccording to the fourth embodiment of the invention.

FIG. 21 shows aspheric parameters pertaining to the optical imaging lensaccording to the fourth embodiment of the invention.

FIG. 22 is a schematic diagram illustrating an optical imaging lensaccording to a fifth embodiment of the invention.

FIGS. 23A to 23D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the fifth embodiment.

FIG. 24 shows detailed optical data of the optical imaging lensaccording to the fifth embodiment of the invention.

FIG. 25 shows aspheric parameters pertaining to the optical imaging lensaccording to the fifth embodiment of the invention.

FIG. 26 is a schematic diagram illustrating an optical imaging lensaccording to a sixth embodiment of the invention.

FIGS. 27A to 27D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the sixth embodiment.

FIG. 28 shows detailed optical data of the optical imaging lensaccording to the sixth embodiment of the invention.

FIG. 29 shows aspheric parameters pertaining to the optical imaging lensaccording to the sixth embodiment of the invention.

FIG. 30 is a schematic diagram illustrating an optical imaging lensaccording to a seventh embodiment of the invention.

FIGS. 31A to 31D are diagrams illustrating a longitudinal sphericalaberration and various aberrations of the optical imaging lens accordingto the seventh embodiment.

FIG. 32 shows detailed optical data of the optical imaging lensaccording to the seventh embodiment of the invention.

FIG. 33 shows aspheric parameters pertaining to the optical imaging lensaccording to the seventh embodiment of the invention.

FIGS. 34 and 35 show values of respective important parameters andrelations thereof of the optical imaging lenses according to the firstto seventh embodiments of the invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

In the present disclosure, the optical system may comprise at least onelens element to receive imaging rays that are incident on the opticalsystem over a set of angles ranging from parallel to an optical axis toa half field of view (HFOV) angle with respect to the optical axis. Theimaging rays pass through the optical system to produce an image on animage plane. The term “a lens element having positive refracting power(or negative refracting power)” means that the paraxial refracting powerof the lens element in Gaussian optics is positive (or negative). Theterm “an object-side (or image-side) surface of a lens element” refersto a specific region of that surface of the lens element at whichimaging rays can pass through that specific region. Imaging rays includeat least two types of rays: a chief ray Lc and a marginal ray Lm (asshown in FIG. 1). An object-side (or image-side) surface of a lenselement can be characterized as having several regions, including anoptical axis region, a periphery region, and, in some cases, one or moreintermediate regions, as discussed more fully below.

FIG. 1 is a radial cross-sectional view of a lens element 100. Tworeferential points for the surfaces of the lens element 100 can bedefined: a central point, and a transition point. The central point of asurface of a lens element is a point of intersection of that surface andthe optical axis I. As illustrated in FIG. 1, a first central point CP1may be present on the object-side surface 110 of lens element 100 and asecond central point CP2 may be present on the image-side surface 120 ofthe lens element 100. The transition point is a point on a surface of alens element, at which the line tangent to that point is perpendicularto the optical axis I. The optical boundary OB of a surface of the lenselement is defined as a point at which the radially outermost marginalray Lm passing through the surface of the lens element intersects thesurface of the lens element. All transition points lie between theoptical axis I and the optical boundary OB of the surface of the lenselement. If multiple transition points are present on a single surface,then these transition points are sequentially named along the radialdirection of the surface with reference numerals starting from the firsttransition point. For example, the first transition point, e.g., TP1,(closest to the optical axis I), the second transition point, e.g., TP2,(as shown in FIG. 4), and the Nth transition point (farthest from theoptical axis I).

The region of a surface of the lens element from the central point tothe first transition point TP1 is defined as the optical axis region,which includes the central point. The region located radially outside ofthe farthest N^(th) transition point from the optical axis I to theoptical boundary OB of the surface of the lens element is defined as theperiphery region. In some embodiments, there may be intermediate regionspresent between the optical axis region and the periphery region, withthe number of intermediate regions depending on the number of thetransition points.

The shape of a region is convex if a collimated ray being parallel tothe optical axis I and passing through the region is bent toward theoptical axis I such that the ray intersects the optical axis I on theimage side A2 of the lens element. The shape of a region is concave ifthe extension line of a collimated ray being parallel to the opticalaxis I and passing through the region intersects the optical axis I onthe object side A1 of the lens element.

Additionally, referring to FIG. 1, the lens element 100 may also have amounting portion 130 extending radially outward from the opticalboundary OB. The mounting portion 130 is typically used to physicallysecure the lens element to a corresponding element of the optical system(not shown). Imaging rays do not reach the mounting portion 130. Thestructure and shape of the mounting portion 130 are only examples toexplain the technologies, and should not be taken as limiting the scopeof the present disclosure. The mounting portion 130 of the lens elementsdiscussed below may be partially or completely omitted in the followingdrawings.

Referring to FIG. 2, optical axis region Z1 is defined between centralpoint CP and first transition point TP1. Periphery region Z2 is definedbetween TP1 and the optical boundary OB of the surface of the lenselement. Collimated ray 211 intersects the optical axis I on the imageside A2 of lens element 200 after passing through optical axis regionZ1, i.e., the focal point of collimated ray 211 after passing throughoptical axis region Z1 is on the image side A2 of the lens element 200at point R in FIG. 2. Accordingly, since the ray itself intersects theoptical axis I on the image side A2 of the lens element 200, opticalaxis region Z1 is convex. On the contrary, collimated ray 212 divergesafter passing through periphery region Z2. The extension line EL ofcollimated ray 212 after passing through periphery region Z2 intersectsthe optical axis I on the object side A1 of lens element 200, i.e., thefocal point of collimated ray 212 after passing through periphery regionZ2 is on the object side A1 at point M in FIG. 2. Accordingly, since theextension line EL of the ray intersects the optical axis I on the objectside A1 of the lens element 200, periphery region Z2 is concave. In thelens element 200 illustrated in FIG. 2, the first transition point TP1is the border of the optical axis region and the periphery region, i.e.,TP1 is the point at which the shape changes from convex to concave.

Alternatively, there is another way for a person having ordinary skillin the art to determine whether an optical axis region is convex orconcave by referring to the sign of “Radius” (the “R” value), which isthe paraxial radius of shape of a lens surface in the optical axisregion. The R value is commonly used in conventional optical designsoftware such as Zemax and CodeV. The R value usually appears in thelens data sheet in the software. For an object-side surface, a positiveR value defines that the optical axis region of the object-side surfaceis convex, and a negative R value defines that the optical axis regionof the object-side surface is concave. Conversely, for an image-sidesurface, a positive R value defines that the optical axis region of theimage-side surface is concave, and a negative R value defines that theoptical axis region of the image-side surface is convex. The resultfound by using this method should be consistent with the methodutilizing intersection of the optical axis by rays/extension linesmentioned above, which determines surface shape by referring to whetherthe focal point of a collimated ray being parallel to the optical axis Iis on the object-side or the image-side of a lens element. As usedherein, the terms “a shape of a region is convex (concave),” “a regionis convex (concave),” and “a convex- (concave-) region,” can be usedalternatively.

FIG. 3, FIG. 4 and FIG. 5 illustrate examples of determining the shapeof lens element regions and the boundaries of regions under variouscircumstances, including the optical axis region, the periphery region,and intermediate regions as set forth in the present specification.

FIG. 3 is a radial cross-sectional view of a lens element 300. Asillustrated in FIG. 3, only one transition point TP1 appears within theoptical boundary OB of the image-side surface 320 of the lens element300. Optical axis region Z1 and periphery region Z2 of the image-sidesurface 320 of lens element 300 are illustrated. The R value of theimage-side surface 320 is positive (i.e., R>0). Accordingly, the opticalaxis region Z1 is concave.

In general, the shape of each region demarcated by the transition pointwill have an opposite shape to the shape of the adjacent region(s).Accordingly, the transition point will define a transition in shape,changing from concave to convex at the transition point or changing fromconvex to concave. In FIG. 3, since the shape of the optical axis regionZ1 is concave, the shape of the periphery region Z2 will be convex asthe shape changes at the transition point TP1.

FIG. 4 is a radial cross-sectional view of a lens element 400. Referringto FIG. 4, a first transition point TP1 and a second transition pointTP2 are present on the object-side surface 410 of lens element 400. Theoptical axis region Z1 of the object-side surface 410 is defined betweenthe optical axis I and the first transition point TP1. The R value ofthe object-side surface 410 is positive (i.e., R>0). Accordingly, theoptical axis region Z1 is convex.

The periphery region Z2 of the object-side surface 410, which is alsoconvex, is defined between the second transition point TP2 and theoptical boundary OB of the object-side surface 410 of the lens element400. Further, intermediate region Z3 of the object-side surface 410,which is concave, is defined between the first transition point TP1 andthe second transition point TP2. Referring once again to FIG. 4, theobject-side surface 410 includes an optical axis region Z1 locatedbetween the optical axis I and the first transition point TP1, anintermediate region Z3 located between the first transition point TP1and the second transition point TP2, and a periphery region Z2 locatedbetween the second transition point TP2 and the optical boundary OB ofthe object-side surface 410. Since the shape of the optical axis regionZ1 is designed to be convex, the shape of the intermediate region Z3 isconcave as the shape of the intermediate region Z3 changes at the firsttransition point TP1, and the shape of the periphery region Z2 is convexas the shape of the periphery region Z2 changes at the second transitionpoint TP2.

FIG. 5 is a radial cross-sectional view of a lens element 500. Lenselement 500 has no transition point on the object-side surface 510 ofthe lens element 500. For a surface of a lens element with no transitionpoint, for example, the object-side surface 510 the lens element 500,the optical axis region Z1 is defined as the region between 0-50% of thedistance between the optical axis I and the optical boundary OB of thesurface of the lens element and the periphery region is defined as theregion between 50%-100% of the distance between the optical axis I andthe optical boundary OB of the surface of the lens element. Referring tolens element 500 illustrated in FIG. 5, the optical axis region Z1 ofthe object-side surface 510 is defined between the optical axis I and50% of the distance between the optical axis I and the optical boundaryOB. The R value of the object-side surface 510 is positive (i.e., R>0).Accordingly, the optical axis region Z1 is convex. For the object-sidesurface 510 of the lens element 500, because there is no transitionpoint, the periphery region Z2 of the object-side surface 510 is alsoconvex. It should be noted that lens element 500 may have a mountingportion (not shown) extending radially outward from the periphery regionZ2.

FIG. 6 is a schematic diagram illustrating an optical imaging lensaccording to a first embodiment of the invention. FIGS. 7A to 7D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the firstembodiment. Referring to FIG. 6, an optical imaging lens 10 includes anaperture 0, a first lens element 1, a second lens element 2, a thirdlens element 3, a fourth lens element 4, a fifth lens element 5, a sixthlens element 6, a seventh lens element 7, an eighth lens element 8, anda filter 9 sequentially arranged from an object side to an image sidealong an optical axis I. When a ray emitted from an object to be shotenters the optical imaging lens 10, an image may be formed on an imageplane 99 after the ray passes through the aperture 0, the first lenselement 1, the second lens element 2, the third lens element 3, thefourth lens element 4, the fifth lens element 5, the sixth lens element6, the seventh lens element 7, the eighth lens element 8, and the filter9. The filter 9 may be an infrared cut-off filter, for example, and isadapted to prevent a portion of infrared light in the ray from beingtransmitted to the image plane 99 and affecting the imaging quality. Inaddition, the object side is a side facing toward the object to be shot,whereas the image side is a side facing toward the image plane 99.

The first lens element 1, the second lens element 2, the third lenselement 3, the fourth lens element 4, the fifth lens element 5, thesixth lens element 6, the seventh lens element 7, the eighth lenselement 8 and the filter 9 respectively have object-side surfaces 15,25, 35, 45, 55, 65, 75, 85, and 95 facing toward the object side andallowing imaging rays to pass through and image-side surfaces 16, 26,36, 46, 56, 66, 76, 86 and 96 facing toward the image side and allowingthe imaging rays to pass through.

To meet the needs for weight reduction of the product, materials of thefirst lens element 1 to the eighth lens element 8 may be plastic.However, the materials of the first lens element 1 to the eighth lenselement 8 are not limited thereto.

In the following, the refracting powers and the surface shapes (convexsurface and concave surface) of the respective lens elements aredescribed with reference to the accompanying drawings.

The first lens element 1 has positive refracting power. On theobject-side surface 15 of the first lens element 1, an optical axisregion 155 and a periphery region 156 are convex. In addition, on theimage-side surface 16 of the first lens element 1, an optical axisregion 165 and a periphery region 166 are concave.

The second lens element 2 has positive refracting power. On theobject-side surface 25 of the second lens element 2, an optical axisregion 255 and a periphery region 256 are convex. In addition, on theimage-side surface 26 of the second lens element 2, an optical axisregion 265 is concave, and a periphery region 266 is convex.

The third lens element 3 has negative refracting power. On theobject-side surface 35 of the third lens element 3, an optical axisregion 355 is convex, and a periphery region 356 is concave. Inaddition, on the image-side surface 36 of the third lens element 3, anoptical axis region 365 is concave, and a periphery region 366 isconvex.

The fourth lens element 4 has positive refracting power. On theobject-side surface 45 of the fourth lens element 4, an optical axisregion 455 is convex, and a periphery region 456 is concave. Inaddition, on the image-side surface 46 of the fourth lens element 4, anoptical axis region 465 and a periphery region 466 are convex.

The fifth lens element 5 has positive refracting power. On theobject-side surface 55 of the fifth lens element 5, an optical axisregion 555 and a periphery region 556 are concave. In addition, on theimage-side surface 56 of the fifth lens element 5, an optical axisregion 565 and a periphery region 566 are convex.

The sixth lens element 6 has negative refracting power. On theobject-side surface 65 of the sixth lens element 6, an optical axisregion 655 is convex, and a periphery region 656 is concave. Inaddition, on the image-side surface 66 of the sixth lens element 6, anoptical axis region 665 is concave, and a periphery region 666 isconvex.

The seventh lens element 7 has positive refracting power. On theobject-side surface 75 of the seventh lens element 7, an optical axisregion 755 is convex, and a periphery region 756 is concave. Inaddition, on the image-side surface 76 of the seventh lens element 7, anoptical axis region 765 is concave, and a periphery region 766 isconvex.

The eighth lens element 8 has negative refracting power. On theobject-side surface 85 of the eighth lens element 8, an optical axisregion 855 and a periphery region 856 are concave. In addition, on theimage-side surface 86 of the eighth lens element 8, an optical axisregion 865 is concave, and a periphery region 866 is convex.

In the optical imaging lens 10, only the above lens elements haverefracting power, and the number of lens elements having a refractingpower in the optical imaging lens 10 is eight.

Detailed optical data of the first embodiment are as shown in FIG. 8. Inaddition, the effective focal length (EFL) of the whole optical imaginglens 10 of the first embodiment is 4.172 mm, the half field of view(HFOV) thereof is 37.033°, the f-number (Fno) thereof is 1.6, the systemlength (TTL) thereof is 5.502 mm, and the image height thereof is 3.238mm. The system length refers to a distance from the object-side surface15 of the first lens element 1 to the image plane 99 along the opticalaxis I.

Besides, in the embodiment, the object-side surfaces and the image-sidesurfaces of the eight lens elements, totaling 16 surfaces, are allaspheric surfaces. In addition, the aspheric surfaces are defined basedon the following equation:

$\begin{matrix}{{Z(Y)} = {{\frac{Y^{2}}{R}\text{/}\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\;{a_{i} \times Y^{i}}}}} & (1)\end{matrix}$

-   -   wherein:    -   Y: a distance from a point on an aspheric curve to the optical        axis I;    -   Z: a depth of an aspheric surface (i.e., a vertical distance        between the point on the aspheric surface that is spaced by the        distance Y from the optical axis I and a tangent plane tangent        to a vertex of the aspheric surface on the optical axis I);    -   R: a radius of curvature of the surface of the lens element        proximate the optical axis I;    -   K: a conic constant;    -   a_(i): an i^(th) aspheric coefficient.

Respective aspheric coefficients of the object-side surfaces 15, 25, 35,45, 55, 65, 75, and 85 and the image-side surfaces 16, 26, 36, 46, 56,66, 76, and 86 in Equation (1) are as shown in FIG. 9. For example, therow number 15 in FIG. 9 indicates that the values are asphericcoefficients of the object-side surface 15 of the first lens element 1.Other rows are arranged based on the same principle.

In addition, relations of important parameters in the optical imaginglens 10 according to the first embodiment are as shown in FIGS. 34 and35. In the optical imaging lens 10 of the first embodiment,

-   -   T1 is a thickness of the first lens element 1 along the optical        axis I;    -   T2 is a thickness of the second lens element 2 along the optical        axis I;    -   T3 is a thickness of the third lens element 3 along the optical        axis I;    -   T4 is a thickness of the fourth lens element 4 along the optical        axis I;    -   T5 is a thickness of the fifth lens element 5 along the optical        axis I;    -   T6 is a thickness of the sixth lens element 6 along the optical        axis I;    -   T7 is a thickness of the seventh lens element 7 along the        optical axis I;    -   T8 is a thickness of the eighth lens element 8 along the optical        axis I;    -   TF is a thickness of the filter 9 along the optical axis I;    -   G12 is an air gap from the first lens element 1 to the second        lens element 2 along the optical axis I;    -   G23 is an air gap from the second lens element 2 to the third        lens element 3 along the optical axis I;    -   G34 is an air gap from the third lens element 3 to the fourth        lens element 4 along the optical axis I;    -   G45 is an air gap from the fourth lens element 4 to the fifth        lens element 5 along the optical axis I;    -   G56 is an air gap from the fifth lens element 5 to the sixth        lens element 6 along the optical axis I;    -   G67 is an air gap from the sixth lens element 6 to the seventh        lens element 7 along the optical axis I;    -   G78 is an air gap from the seventh lens element 7 to the eighth        lens element 8 along the optical axis I;    -   G8F is an air gap from the eighth lens element 8 to the filter 9        along the optical axis I;    -   GFP is an air gap from the filter 9 to the image plane 99 along        the optical axis I;    -   AAG is a sum of the seven air gaps from the first lens element 1        to the eighth lens element 8 along the optical axis I;    -   ALT is a sum of the thicknesses of the first lens element 1, the        second lens element 2, the third lens element 3, the fourth lens        element 4, the fifth lens element 5, the sixth lens element 6,        the seventh lens element 7, and the eighth lens element 8 along        the optical axis I;    -   EFL is an effective focal length of the optical imaging lens 10;    -   BFL is a distance from the image-side surface 86 of the eighth        lens element 8 to the image plane 99 along the optical axis I;    -   TTL is a distance from the object-side surface 15 of the first        lens element 1 to the image plane 99 along the optical axis I;    -   TL is a distance from the object-side surface 15 of the first        lens element 1 to the image-side surface 86 of the eighth lens        element 8 along the optical axis I; and    -   HFOV is a half field of view of the optical imaging lens 10.    -   Besides, it is further defined as follows:    -   V1 is an Abbe number of the first lens element 1, wherein the        Abbe number may also be referred to as a dispersion coefficient;    -   V2 is an Abbe number of the second lens element 2;    -   V3 is an Abbe number of the third lens element 3;    -   V4 is an Abbe number of the fourth lens element 4;    -   V5 is an Abbe number of the fifth lens element 5;    -   V6 is an Abbe number of the sixth lens element 6;    -   V7 is an Abbe number of the seventh lens element 7;    -   V8 is an Abbe number of the eighth lens element 8;    -   f1 is a focal length of the first lens element 1;    -   f2 is a focal length of the second lens element 2;    -   f3 is a focal length of the third lens element 3;    -   f4 is a focal length of the fourth lens element 4;    -   f5 is a focal length of the fifth lens element 5;    -   f6 is a focal length of the sixth lens element 6;    -   f7 is a focal length of the seventh lens element 7;    -   f8 is a focal length of the eighth lens element 8;    -   n1 is a refractive index of the first lens element 1;    -   n2 is a refractive index of the second lens element 2;    -   n3 is a refractive index of the third lens element 3;    -   n4 is a refractive index of the fourth lens element 4;    -   n5 is a refractive index of the fifth lens element 5;    -   n6 is a refractive index of the sixth lens element 6;    -   n7 is a refractive index of the seventh lens element 7; and    -   n8 is a refractive index of the eighth lens element 8.

Referring to FIGS. 7A to 7D, FIG. 7A illustrates the longitudinalspherical aberration of optical imaging lens 10 of the first embodimentwhen the pupil radius of the first embodiment is 1.3037 mm. In FIG. 7A,the curves representing the respective wavelengths are close to eachother and approach the center, indicating that off-axis rays indifferent heights at the respective wavelengths are concentrated in avicinity of the imaging point. Based on extents of deviation of thecurves for the respective wavelengths, imaging point deviations of theoff-axis rays in different heights are controlled within a range from−0.019 mm to 0.014 mm. Therefore, the spherical aberration of the samewavelength is reduced in the optical imaging lens of the firstembodiment. In addition, the distances among the three representingwavelengths are close, indicating that imaging positions of rays ofdifferent wavelengths are concentrated. Hence, chromatic aberration isalso suppressed.

FIGS. 7B and 7C respectively illustrate the field curvature aberrationin the sagittal direction and the field curvature aberration in thetangential direction on the image plane 99 when the wavelength is 650mm, 555 mm, and 470 mm. In FIGS. 7B and 7C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.05 mmto 0.02 mm, indicating that the optical imaging lens of the firstembodiment is able to effectively reduce aberration.

FIG. 7D illustrates the distortion aberration on the image plane 99 whenthe wavelength is 650 mm, 555 mm, and 470 mm. FIG. 7D illustrating thedistortion aberration indicates that the distortion aberration ismaintained within a range from 0 to 2.5%, indicating that the distortionaberration of the optical imaging lens of the first embodiment alreadysatisfies the imaging quality requirement of an optical system.

Based on the above, compared with known optical lenses, the opticalimaging lens 10 of the first embodiment is able to render a desirableimaging quality under a condition that the system length is reduced toabout 5.502 mm. Besides, in the optical imaging lens of the firstembodiment, the system length is reduced and the shooting angle isexpanded under a condition of maintaining a desirable opticalperformance. Thus, a product design capable of miniaturization andexpanding the field of view is achieved.

FIG. 10 is a schematic diagram illustrating an optical imaging lensaccording to a second embodiment of the invention. FIGS. 11A to 11D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the secondembodiment. Referring to FIG. 10, the second embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, an optical axisregion 267 of the image-side surface 26 of the second lens element 2 isconvex. To clearly illustrate the drawing, some reference numeralsindicating surface shapes same as those of the first embodiment areomitted in FIG. 10.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 12. In addition, the EFL of the whole optical imaging lens 10 ofthe second embodiment is 4.275 mm, the HFOV thereof is 36.830°, the Fnothereof is 1.6, the TTL thereof is 5.686 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the second embodimentin Equation (1) are shown in FIG. 13.

In addition, relations of important parameters in the optical imaginglens 10 according to the second embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 11A to 11D, in FIG. 11A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.025 mm to 0.015 mm when thepupil radius is 1.3358 mm. In FIGS. 11B and 11C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.07 mmto 0.01 mm. In FIG. 11D illustrating the distortion aberration, thedistortion aberration is maintained within a range from −0.2% to 1.25%.Based on the above, compared with known optical lenses, the opticalimaging lens 10 of the second embodiment is able to render a desirableimaging quality under a condition that the system length is reduced toabout 5.686 mm.

In addition, based on the above, the second embodiment is more desirableover the first embodiment in that the distortion aberration of thesecond embodiment is less than that of the first embodiment.

FIG. 14 is a schematic diagram illustrating an optical imaging lensaccording to a third embodiment of the invention. FIGS. 15A to 15D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the thirdembodiment. Referring to FIG. 14, the third embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, an optical axisregion 267 of the image-side surface 26 of the second lens element 2 isconvex. To clearly illustrate the drawing, some reference numeralsindicating surface shapes same as those of the first embodiment areomitted in FIG. 14.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 16. In addition, the EFL of the whole optical imaging lens 10 ofthe third embodiment is 4.325 mm, the HFOV thereof is 36.904°, the Fnothereof is 1.6, the TTL thereof is 5.816 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the third embodimentin Equation (1) are shown in FIG. 17.

In addition, relations of important parameters in the optical imaginglens 10 according to the third embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 15A to 15D, in FIG. 15A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.019 mm to 0.02 mm when thepupil radius is 1.3515 mm. In FIGS. 15B and 15C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.05 mmto 0.035 mm. In FIG. 15D illustrating the distortion aberration, thedistortion aberration is maintained within a range from −1% to 0.6%.Based on the above, compared with known optical lenses, the opticalimaging lens 10 of the third embodiment is able to render a desirableimaging quality under a condition that the system length is reduced toabout 5.816 mm.

In addition, based on the above, the third embodiment is more desirableover the first embodiment in that the distortion aberration of the thirdembodiment is less than that of the first embodiment.

FIG. 18 is a schematic diagram illustrating an optical imaging lensaccording to a fourth embodiment of the invention. FIGS. 19A to 19D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the fourthembodiment. Referring to FIG. 18, the fourth embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, a periphery region368 of the image-side surface 36 of the third lens element 3 and aperiphery region 568 of the image-side surface 56 of the fifth lenselement 5 are concave. To clearly illustrate the drawing, some referencenumerals indicating surface shapes same as those of the first embodimentare omitted in FIG. 18.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 20. In addition, the EFL of the whole optical imaging lens 10 ofthe fourth embodiment is 3.639 mm, the HFOV thereof is 37.332°, the Fnothereof is 1.6, the TTL thereof is 4.695 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the fourth embodimentin Equation (1) are shown in FIG. 21.

In addition, relations of important parameters in the optical imaginglens 10 according to the fourth embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 19A to 19D, in FIG. 19A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.06 mm to 0.05 mm when thepupil radius is 1.1372 mm. In FIGS. 19B and 19C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.25 mmto 0.05 mm. In FIG. 19D illustrating the distortion aberration, thedistortion aberration is maintained within a range from 0% to 15%. Basedon the above, compared with known optical lenses, the optical imaginglens 10 of the fourth embodiment is able to render a desirable imagingquality under a condition that the system length is reduced to about4.695 mm.

In addition, based on the above, the fourth embodiment is more desirableover the first embodiment in that the system length of the opticalimaging lens 10 of the fourth embodiment is shorter than that of thefirst embodiment, and the HFOV of the fourth embodiment is greater thanthat of the first embodiment.

FIG. 22 is a schematic diagram illustrating an optical imaging lensaccording to a fifth embodiment of the invention. FIGS. 23A to 23D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the fifthembodiment. Referring to FIG. 22, the fifth embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, an optical axisregion 267 of the image-side surface 26 of the second lens element 2 anda periphery region 858 of the object-side surface 85 of the eighth lenselement 8 are convex. To clearly illustrate the drawing, some referencenumerals indicating surface shapes same as those of the first embodimentare omitted in FIG. 22.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 24. In addition, the EFL of the whole optical imaging lens 10 ofthe fifth embodiment is 4.144 mm, the HFOV thereof is 37.116°, the Fnothereof is 1.6, the TTL thereof is 5.577 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the fifth embodimentin Equation (1) are shown in FIG. 25.

In addition, relations of important parameters in the optical imaginglens 10 according to the fifth embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 23A to 23D, in FIG. 23A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.025 mm to 0.02 mm when thepupil radius is 1.2949 mm. In FIGS. 23B and 23C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.07 mmto 0.09 mm. In FIG. 23D illustrating the distortion aberration, thedistortion aberration is maintained within a range from −0.5% to 2.5%.Based on the above, compared with known optical lenses, the opticalimaging lens 10 of the fifth embodiment is able to render a desirableimaging quality under a condition that the system length is reduced toabout 5.577 mm.

In addition, based on the above, the fifth embodiment is more desirableover the first embodiment in that the HFOV of the fifth embodiment isgreater than that of the first embodiment.

FIG. 26 is a schematic diagram illustrating an optical imaging lensaccording to a sixth embodiment of the invention. FIGS. 27A to 27D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the sixthembodiment. Referring to FIG. 26, the sixth embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, a periphery region568 of the image-side surface 56 of the fifth lens element 5 is concave.To clearly illustrate the drawing, some reference numerals indicatingsurface shapes same as those of the first embodiment are omitted in FIG.26.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 28. In addition, the EFL of the whole optical imaging lens 10 ofthe sixth embodiment is 3.989 mm, the HFOV thereof is 37.193°, the Fnothereof is 1.6, the TTL thereof is 5.281 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the sixth embodimentin Equation (1) are shown in FIG. 29.

In addition, relations of important parameters in the optical imaginglens 10 according to the sixth embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 27A to 27D, in FIG. 27A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.065 mm to 0.026 mm when thepupil radius is 1.2464 mm. In FIGS. 27B and 27C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.16 mmto −0.025 mm. In FIG. 27D illustrating the distortion aberration, thedistortion aberration is maintained within a range from 0% to 5%. Basedon the above, compared with known optical lenses, the optical imaginglens 10 of the sixth embodiment is able to render a desirable imagingquality under a condition that the system length is reduced to about5.281 mm.

In addition, based on the above, the sixth embodiment is more desirableover the first embodiment in that the system length of the opticalimaging lens 10 of the sixth embodiment is shorter than that of thefirst embodiment, and the HFOV of the sixth embodiment is greater thanthat of the first embodiment.

FIG. 30 is a schematic diagram illustrating an optical imaging lensaccording to a seventh embodiment of the invention. FIGS. 31A to 31D arediagrams illustrating a longitudinal spherical aberration and variousaberrations of the optical imaging lens according to the seventhembodiment. Referring to FIG. 30, the seventh embodiment of the opticalimaging lens 10 is similar to the first embodiment, and the differencestherebetween mainly include the following: respective optical data,aspheric coefficients and parameters among the lens elements aredifferent to a more or lesser extent. In addition, a periphery region258 of the object-side surface 25 of the second lens element 2, anoptical axis region 457 of the object-side surface 45 of the fourth lenselement 4, and a periphery region 668 of the image-side surface 66 ofthe sixth lens element 6 are concave, and a periphery region 858 of theobject-side surface 85 of the eighth lens element 8 is convex. Toclearly illustrate the drawing, some reference numerals indicatingsurface shapes same as those of the first embodiment are omitted in FIG.30.

Detailed optical data of the optical imaging lens 10 are as shown inFIG. 32. In addition, the EFL of the whole optical imaging lens 10 ofthe seventh embodiment is 3.893 mm, the HFOV thereof is 37.121°, the Fnothereof is 1.6, the TTL thereof is 5.211 mm, and the image heightthereof is 3.238 mm.

Respective aspheric coefficients of the object-side surfaces and theimage-side surfaces of the eight lens elements of the seventh embodimentin Equation (1) are shown in FIG. 33.

In addition, relations of important parameters in the optical imaginglens 10 according to the seventh embodiment are as shown in FIGS. 34 and35.

Referring to FIGS. 31A to 31D, in FIG. 31A illustrating the longitudinalspherical aberration, imaging point deviations of the off-axis rays indifferent heights are controlled within −0.25 mm to 0.05 mm when thepupil radius is 1.2167 mm. In FIGS. 31B and 31C illustrating the fieldcurvature aberrations, focal length variations of the three representingwavelengths in the whole field range fall within a range from −0.25 mmto 0.35 mm. In FIG. 31D illustrating the distortion aberration, thedistortion aberration is maintained within a range from 0% to 2.5%.Based on the above, compared with known optical lenses, the opticalimaging lens 10 of the seventh embodiment is able to render a desirableimaging quality under a condition that the system length is reduced toabout 5.211 mm.

In addition, based on the above, the seventh embodiment is moredesirable over the first embodiment in that the system length of theoptical imaging lens 10 of the seventh embodiment is shorter than thatof the first embodiment, the HFOV of the seventh embodiment is greaterthan that of the first embodiment, and the distortion aberration of theseventh embodiment is less than that of the first embodiment.

In the respective embodiments of the invention, the optical imaging lensexhibits a small Fno and renders a desirable imaging quality. Besides,the spherical aberration and the image aberration of the optical systemmay be corrected and the distortion aberration thereof may be reducedthrough the design of concave/convex surface shapes of the lenselements. For example, the optical axis region of the image-side surfaceof the third lens element is concave, the optical axis region of theobject-side surface of the fifth lens element is concave, the peripheryregion of the image-side surface of the fifth lens element is convex,the optical axis region of the object-side surface of the sixth lenselement is convex, and the optical axis region of the object-sidesurface of the seventh lens element is convex. In addition, the designthat the first lens element and the second lens element both havepositive refracting power may facilitate convergence of rays, so as toreduce the system length of the optical imaging lens. Moreover, toreduce the system length and ensure the imaging quality, the air gapbetween lens elements or the thickness of the lens element may bereduced. Nevertheless, considering the manufacturing complexity, aconfiguration according to the embodiments of the invention is desirableif at least one of the following conditions is satisfied.

ALT/(T4+G45)≤4.800, a preferable range is 3.000≤ALT/(T4+G45)≤4.800;

(G34+G78)/T3≤3.500, a preferable range is 1.700≤(G34+G78)/T3≤3.500;

AAG/(G12+G23+G67)≤5.000, a preferable range is1.700≤AAG/(G12+G23+G67)≤5.000;

TL/BFL≥3.500, a preferable range is 3.500≤TL/BFL≤5.100;

(T6+T7+T8)/(G12+G45+G67)≤3.500, a preferable range is1.000≤(T6+T7+T8)/(G12+G45+G67)≤3.500;

(T1+T2+T4)/(T5+T6)≥2.000, a preferable range is2.000≤(T1+T2+T4)/(T5+T6)≤3.200;

(G45+T5+G56)/T6≥1.800, a preferable range is1.800≤(G45+T5+G56)/T6≤2.600;

AAG/(G45+T5+G67)≤2.200, a preferable range is1.200≤AAG/(G45+T5+G67)≤2.200;

(T4+G45+T5)/(G56+T6)≥2.000, a preferable range is2.000≤(T4+G45+T5)/(G56+T6)≤4.500;

(T1+T2+T3)/(G23+G34)≥2.700, a preferable range is2.700≤(T1+T2+T3)/(G23+G34)≤4.000;

AAG/(G23+G45)≤5.500, a preferable range is 2.800≤AAG/(G23+G45)≤5.500;

ALT/(T3+T4)≤4.300, a preferable range is 3.000≤ALT/(T3+T4)≤4.300;

(G78+T8)/G67≤6.500, a preferable range is 1.000≤(G78+T8)/G67≤6.500;

(T4+T6)/G45≤6.000, a preferable range is 2.200≤(T4+T6)/G45≤6.000;

(G34+G45)/G78≥1.500, a preferable range is 1.500≤(G34+G45)/G78≤2.300;

(T5+T6)/T3≤3.100, a preferable range is 2.100≤(T5+T6)/T3≤3.100;

EFL/(G45+T5)≤8.500, a preferable range is 5.600≤EFL/(G45+T5)≤8.500; and

T6/(G12+G45)≤1.600, a preferable range is 0.400≤T6/(G12+G45)≤1.600.

Considering the unpredictability in the design of optical system, underthe framework of the embodiments of the invention, the embodiments ofthe invention may have a shorter system length, a greater field of view,a desirable imaging quality, or a facilitated assembling yield rate ifthe above conditions are satisfied.

In view of the foregoing, the optical imaging lens according to one orsome exemplary embodiments of the invention is able to render one orsome of the following:

i. The longitudinal spherical aberrations, field curvature aberrations,and distortion aberrations of the respective embodiments of theinvention meet the protocol of use. In addition, the off-axis rays ofthe three representing wavelengths, i.e., 650 nm, 555 nm, and 470 nm, indifferent heights are all concentrated at a vicinity of the imagingpoint. The extents of deviation of the respective curves show that theimaging point deviations of the off-axis rays in different heights arecontrolled, so a desirable suppressing ability against sphericalaberration, image aberration, and distortion aberration is rendered. Theimaging quality data further suggest that the distances among the threerepresenting wavelengths, i.e., 650 nm, 555 nm, and 470 nm, are close toeach other, indicating that the embodiments of the invention are able todesirably concentrate rays of different wavelengths in various statesand exhibit an excellent dispersion suppressing ability. Therefore, theembodiments of the invention render a desirable optical performance.

ii. An arbitrary number of the exemplary limiting relations listed abovemay also be arbitrarily and optionally combined and incorporated intothe embodiments of the invention. The invention shall not be construedas being limited thereto.

iii. The maximum and minimum numeral values derived from thecombinations of the optical parameters disclosed in the embodiments ofthe invention may all be applicable and enable people skill in thepertinent art to implement the invention.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. An optical imaging lens, comprising a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, a sixth lens element, a seventh lenselement, and an eighth lens element sequentially arranged along anoptical axis from an object side to an image side, each of the firstlens element to the eighth lens element comprising an object-sidesurface facing toward the object side and allowing imaging rays to passthrough and an image-side surface facing toward the image side andallowing the imaging rays to pass through, wherein: the first lenselement has positive refracting power; the second lens element haspositive refracting power; an optical axis region of the object-sidesurface of the second lens element is convex; a periphery region of theobject-side surface of the seventh lens element is concave; and theeight lens elements are the only lens elements having refracting powerin the optical imaging lens, wherein the optical imaging lens satisfies:(T1+T2+T4)/(T5+T6)≥2.000 and AAG/(G12+G23+G67)≤5.000, wherein T1 is athickness of the first lens element along the optical axis, T2 is athickness of the second lens element along the optical axis, T4 is athickness of the fourth lens element along the optical axis, T5 is athickness of the fifth lens element along the optical axis, T6 is athickness of the sixth lens element along the optical axis, AAG is a sumof seven air gaps from the first lens element to the eighth lens elementalong the optical axis, G12 is an air gap from the first lens element tothe second lens element along the optical axis, G23 is an air gap fromthe second lens element to the third lens element along the opticalaxis, and G67 is an air gap from the sixth lens element to the seventhlens element along the optical axis.
 2. The optical imaging lens asclaimed in claim 1, wherein the optical imaging lens satisfies:TL/BFL≥3.500, wherein TL is a distance from the object-side surface ofthe first lens element to the image-side surface of the eighth lenselement along the optical axis, and BFL is a distance from theimage-side surface of the eighth lens element to an image plane alongthe optical axis.
 3. The optical imaging lens as claimed in claim 1,wherein the optical imaging lens satisfies:(T6+T7+T8)/(G12+G45+G67)≤3.500, wherein T7 is a thickness of the seventhlens element along the optical axis, T8 is a thickness of the eighthlens element along the optical axis, and G45 is an air gap from thefourth lens element to the fifth lens element along the optical axis. 4.The optical imaging lens as claimed in claim 1, wherein the opticalimaging lens satisfies: 3.612≤ALT/(T3+G67)≤10.154, wherein ALT is a sumof thicknesses of the first lens element, the second lens element, thethird lens element, the fourth lens element, the fifth lens element, thesixth lens element, the seventh lens element, and the eighth lenselement along the optical axis, and T3 is a thickness of the third lenselement along the optical axis.
 5. The optical imaging lens as claimedin claim 1, wherein the optical imaging lens satisfies:3.524≤EFL/(T1+G12+G67)≤8.035, wherein EFL is an effective focal lengthof the optical imaging lens.
 6. The optical imaging lens as claimed inclaim 1, wherein the optical imaging lens satisfies:1.106≤(T2+T4+T5)/BFL≤1.754, wherein BFL is a distance from theimage-side surface of the eighth lens element to an image plane alongthe optical axis.
 7. The optical imaging lens as claimed in claim 1,wherein the optical imaging lens satisfies:1.054≤AAG/(G34+T4+G56)≤2.412, wherein G34 is an air gap from the thirdlens element to the fourth lens element along the optical axis, and G56is an air gap from the fifth lens element to the sixth lens elementalong the optical axis.
 8. An optical imaging lens, comprising a firstlens element, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, a sixth lens element, a seventh lenselement, and an eighth lens element sequentially arranged along anoptical axis from an object side to an image side, each of the firstlens element to the eighth lens element comprising an object-sidesurface facing toward the object side and allowing imaging rays to passthrough and an image-side surface facing toward the image side andallowing the imaging rays to pass through, wherein: the first lenselement has positive refracting power; the second lens element haspositive refracting power; an optical axis region of the image-sidesurface of the sixth lens element is concave; and the eight lenselements are the only lens elements having refracting power in theoptical imaging lens, wherein the optical imaging lens satisfies:(T1+T2+T4)/(T5+T6)≤2.000, (T6+T7+T8)/(G12+G45+G67)≤3.500 andAAG/(G12+G23+G67)≤5.000, wherein T1 is a thickness of the first lenselement along the optical axis, T2 is a thickness of the second lenselement along the optical axis, T4 is a thickness of the fourth lenselement along the optical axis, T5 is a thickness of the fifth lenselement along the optical axis, T6 is a thickness of the sixth lenselement along the optical axis, T7 is a thickness of the seventh lenselement along the optical axis, T8 is a thickness of the eighth lenselement along the optical axis, AAG is a sum of seven air gaps from thefirst lens element to the eighth lens element along the optical axis,G12 is an air gap from the first lens element to the second lens elementalong the optical axis, G23 is an air gap from the second lens elementto the third lens element along the optical axis, G45 is an air gap fromthe fourth lens element to the fifth lens element along the opticalaxis, and G67 is an air gap from the sixth lens element to the seventhlens element along the optical axis.
 9. The optical imaging lens asclaimed in claim 8, wherein the optical imaging lens satisfies:(G78+T8)/G67≤6.500, wherein G78 is an air gap from the seventh lenselement to the eighth lens element along the optical axis.
 10. Theoptical imaging lens as claimed in claim 8, wherein the optical imaginglens satisfies: 1.548≤TTL/(ALT+G23)≤1.893, wherein TTL is a distancefrom the object-side surface of the first lens element to an image planealong the optical axis, and ALT is a sum of thicknesses of the firstlens element, the second lens element, the third lens element, thefourth lens element, the fifth lens element, the sixth lens element, theseventh lens element, and the eighth lens element along the opticalaxis.
 11. The optical imaging lens as claimed in claim 8, wherein theoptical imaging lens satisfies: 1.419≤(T6+T7+T8)/(G12+T2)≤2.291.
 12. Theoptical imaging lens as claimed in claim 8, wherein the optical imaginglens satisfies: 4.103≤TL/(G12 T2+G23+T3)≤5.294, wherein TL is a distancefrom the object-side surface of the first lens element to the image-sidesurface of the eighth lens element along the optical axis, and T3 is athickness of the third lens element along the optical axis.
 13. Theoptical imaging lens as claimed in claim 8, wherein the optical imaginglens satisfies: 1.667≤T2/T3≤2.396, wherein T3 is a thickness of thethird lens element along the optical axis.
 14. The optical imaging lensas claimed in claim 8, wherein the optical imaging lens satisfies:4.391≤EFL/(T2+G34)≤6.224, wherein EFL is an effective focal length ofthe optical imaging lens, and G34 is an air gap from the third lenselement to the fourth lens element along the optical axis.
 15. Anoptical imaging lens, comprising a first lens element, a second lenselement, a third lens element, a fourth lens element, a fifth lenselement, a sixth lens element, a seventh lens element, and an eighthlens element sequentially arranged along an optical axis from an objectside to an image side, each of the first lens element to the eighth lenselement comprising an object-side surface facing toward the object sideand allowing imaging rays to pass through and an image-side surfacefacing toward the image side and allowing the imaging rays to passthrough, wherein: the first lens element has positive refracting power;the second lens element has positive refracting power; a peripheryregion of the image-side surface of the seventh lens element is convex;and the eight lens elements are the only lens elements having refractingpower in the optical imaging lens, wherein the optical imaging lenssatisfies: (T1+T2+T4)/(T5+T6)≥2.000, (T6+T7+T8)/(G12+G45+G67)≤3.500 andAAG/(G12+G23+G67)≤5.000, wherein T1 is a thickness of the first lenselement along the optical axis, T2 is a thickness of the second lenselement along the optical axis, T4 is a thickness of the fourth lenselement along the optical axis, T5 is a thickness of the fifth lenselement along the optical axis, T6 is a thickness of the sixth lenselement along the optical axis, T7 is a thickness of the seventh lenselement along the optical axis, T8 is a thickness of the eighth lenselement along the optical axis, AAG is a sum of seven air gaps from thefirst lens element to the eighth lens element along the optical axis,G12 is an air gap from the first lens element to the second lens elementalong the optical axis, G23 is an air gap from the second lens elementto the third lens element along the optical axis, G45 is an air gap fromthe fourth lens element to the fifth lens element along the opticalaxis, and G67 is an air gap from the sixth lens element to the seventhlens element along the optical axis.
 16. The optical imaging lens asclaimed in claim 15, wherein the optical imaging lens satisfies:(G34+G45)/G78≥1.500, wherein G34 is an air gap from the third lenselement to the fourth lens element along the optical axis, and G78 is anair gap from the seventh lens element to the eighth lens element alongthe optical axis.
 17. The optical imaging lens as claimed in claim 15,wherein the optical imaging lens satisfies: (T5+T6)/T3≤3.100, wherein T3is a thickness of the third lens element along the optical axis.
 18. Theoptical imaging lens as claimed in claim 5, wherein the optical imaginglens satisfies: 0.358≤T5/(G12+G67)≤2.254.
 19. The optical imaging lensas claimed in claim 15, wherein the optical imaging lens satisfies:1.227≤(T4+T5)/(G12+G78)≤2.783, wherein G78 is an air gap from theseventh lens element to the eighth lens element along the optical axis.20. The optical imaging lens as claimed in claim 15, wherein the opticalimaging lens satisfies: 1.936≤AAG/(G23+T5+G56)≤3.519, wherein G56 is anair gap from the fifth lens element to the sixth lens element along theoptical axis.